getting to the fuel to create a vapor-lock problem, but there is certainly
enough to cause extra internal pressure from fuel expansion inside the
tank. And with the one-way valve
installed, this pressure can’t escape.
Remove the one-way valve and the
pressure inside the fuel tank should
return to normal. It is possible the
extra fuel pressure is overwhelming
your carb’s float valve and causing
flooding. Flooded, hot engines are
very hard to start, usually requiring
full throttle and a lot of cranking to
get them running again. ❏